Light-duty liquid (LDL) or gel detergent compositions useful for manual dishwashing are well known in the art. Such products are generally formulated to provide a number of widely diverse performance and aesthetics properties and characteristics. First and foremost, liquid or gel dishwashing products must be formulated with types and amounts of surfactants and other cleaning adjuvants that will provide acceptable solubilization and removal of food soils, especially greasy soils, from dishware being cleaned with, or in aqueous solutions formed from such products. Thus, there is a continuing effort by formulators of liquid dishwashing compositions to incorporate additional components into LDL detergents to provide consumers with improved cleaning benefits.
Diamines are a type of nitrogenous compound which can improve the cleaning performance of liquid dishwashing detergent compositions, in particular the cleaning of greasy, hydrophobic soils on dishware or other kitchen articles. However, diamines can also cause extremely potent malodors, such as the unpleasant fragrance associated with permanent kits commonly used to curl hair.
Also, nitrogen-containing surfactants and polymers can provide both cleaning and sudsing advantages, but frequently contain amine impurities as by-products in commercial materials. When the composition exceeds the pKa of these amine impurities, the resultant free amine can be malodors. Consequently, it has been difficult to formulate a malodor-free light duty liquid at pH higher than 8.5.
Typically malodors associated with liquid dishwashing detergents are “masked” (covered up) by placing a perfume composition in the liquid dishwashing detergent, which when used in sufficient quantities, would mask the malodor emanating from the liquid detergent. These perfumes also provided the added benefit that a desirable fragrance, such as a lemon scent, could be imparted to the liquid detergent product.
However, some malodors cannot be masked simply by adding perfumes to the detergent. For example, when a particular malodor is highly volatile (and therefore diffuses quickly into the air) and/or when a particular malodor is extremely potent, it may be difficult to add a sufficient amount of perfume without giving the liquid dishwashing detergent a strong, perfumed odor. Given the foregoing there is a continuing need to formulate liquid dishwashing detergents that provide excellent cleaning benefits, but do not have malodors associated with them. Accordingly a benefit of the present invention is that a liquid dishwashing detergent is provided which incorporates certain nitrogen-containing components (e.g. diamines) which are capable of providing excellent cleaning performance but which is free of the malodors generally associated with the use of these components. The present invention also relates to a perfume compositions suitable for use in liquid dishwashing detergents.
The benefits of this invention can be provided for and included in a broader range of products than just LDLs. Such products include may liquid hand soap, shampoo, after shave, cologne and personal deodorants, other personal care compositions, hard surface cleaners and a variety of other home and personal care products in which nitrogenous compounds like amines may be present and it is desirable to mask any malodors that they may generate.